#include <iostream>

void swap(int &a, int &b)
{
    int c = a;
    a = b;
    b = c;

}

class student
{
private:
    int age;
    int heavy;
public:
    student();
    student(int a, int h);
    ~student();
};
student::student (int a, int h)
{
    age = a;
    heavy = h;
    printf("there is student(int a, int h)\n");
}


int main()
{
    int a = 10;
    int b = 20;
    swap(a, b);
    printf("a = %d, b = %d\n", a, b);

    
    return 0;
}